staging: wfx: simplify hif_update_ie()

hif_update_ie() is only called to change the beacon template. So,
specialize this function and simplify the way to call it.

Signed-off-by: Jérôme Pouiller <jerome.pouiller@silabs.com>
Link: https://lore.kernel.org/r/20200115135338.14374-29-Jerome.Pouiller@silabs.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>